Updated Fingerprint enrollment logging

Test: Verified regular fingerprint enrollment correctly logged
enrollment.
Test: Verified that the find fingerprint sensor activity no longer
falsely reports a failed enrollment.
Bug: 175316123

Fingerprint enrollment shows a find sensor screen which makes a call to
FingerprintManager.enroll(), the purpose is to get the user to locate
the sensor. The consequence was that logging built into the framework
was incorrectly logging a failed enrollment after cancellation.

Change-Id: I2ec27120943e1ce3d70f5ca2f3221a4b3b571c39